The epoch of reionization (EoR) is a period in the history of the universe when the first stars and galaxies formed and started emitting intense ultraviolet radiation that ionized the neutral hydrogen gas that filled the universe. This process began around 400 million years after the Big Bang and lasted for several hundred million years. The EoR marked a critical transition in the universe's evolution, as it transformed the opaque neutral universe into a transparent ionized one, allowing light to travel freely across vast distances. Studying the epoch of reionization is crucial for understanding the formation and evolution of the first structures in the universe and how they shaped the cosmos as we know it today. Researchers use a variety of observational techniques, such as studying the imprint of the EoR on the cosmic microwave background radiation and distant galaxies, to gain insights into this important phase in cosmic history.